By " Stupid Question"
I thought you meant something like ...
What would chairs look like if our knees bent the other way ?
Randy
Thats a good one!!! LMAO
There should be no reason to filter that air, unless you are in a very dirty / dusty enviroment because it is only used for cumbustion. any debris would be burned.
I'm no pro either but I've used a 1 inch thick pleated filter on the air return grille along with the 3 inch filter that is located at the furnace with no issues.
I've fished Eagle Lake for the last 23 years and really haven't heard alot about them. I do look forward to seeing their sign on the 502 though because it means I'm getting closer to my destination.